Equis ISSN 2398-2977

Foot: hoof wall fracture

Synonym(s): Hoof wall cracks, sand crack, grass crack, toe crack, quarter crack, heel crack

Contributor(s): Prof Michel A Collier, Simon Curtis, Robert A Eustace, Graham Munroe

Introduction

  • Cause: weak brittle hoof wall, rough ground, too long an interval between routine trimming, poor diet and overuse, selenium toxicosis, hoof imbalance and inappropriate shoeing.
  • Signs: self-evident; with many cracks no lameness is apparent.
  • Diagnosis: careful examination of the foot preferable with hoof testers; rule out other causes of lameness if necessary with diagnostic analgesic techniques; foot radiographs.
  • Treatment: for underlying causes; stabilize crack; pain relief; treat infection if present; correct hoof imbalance.
  • Prognosis: depends on the type of crack and underlying cause.
Print off the Owner factsheet on Caring for your horse's feet to give to your clients.

Pathogenesis

Etiology

  • Unknown.
  • Hoof deformities, eg chronic founder   Foot: laminitis   and flexural deformities of the distal interphalangeal joint (clubfoot)   DIP joint: flexural deformity  can often lead to toe cracks.
  • Alternating excessively wet and dry conditions.
  • Nutrient deficiencies.
  • Inadequate, incorrect or absent shoeing.
  • Poor foot maintenance, eg low weak underrun heel, long toe, flat sole, mediolateral foot imbalance.
  • Damage to the coronary band due to trauma or infection.
  • Poor hoof quality.

Specific

  • Mediolateral foot imbalance causing the two sides of the hoof wall to strike the ground asynchronously causing stresses in the horn wall.
  • Dorsopalmar/plantar foot imbalance with excessively long toe and/or low weak heel conformation will concentrate stresses at the toe and heel/quarter junction.
  • Toe-in/varus fetlock - lateral quarter cracks   Musculoskeletal: angular deformity  .
  • Toe-out/carpal valgus - medial quarter cracks   Musculoskeletal: angular deformity  .

Pathophysiology

  • Poor hoof quality including brittle hooves.
  • Severe foot imbalance or overwork   →   damage to the hoof wall.
  • Instability of the hoof capsule leads to pain and lameness, due to pinching of the underlying corium.
  • Loss of hoof wall integrity predisposes to infection.
  • Grass cracksdevelop at the distal end of the wall and propagate proximally over time.
  • Sand cracksdevelop at or just below the coronary band and usually progress distally. Previous injuries to the coronary band can predispose to weak defective horn predisposing to cracks.
  • They can be further categorized according to:
    • The position of the foot: toe, heel or quarter.
    • Completeness: where complete runs the entire length of the wall, and incomplete only part of the wall is affected.
  • Cracks can vary in depth of damage to the hoof wall from partial to full thickness:
    • Full thickness cracks: often unstable, create shear forces which propagate the crack further, and are often painful. Infection is more likely in full thickness cracks, increasing pain and lameness.
    • Partial thickness cracks: hardly ever painful and require minimal specific treatment.
  • Quarter and heel cracksdevelop in athletic horses due to imbalance   Musculoskeletal: conformation  , fast work, poor farriery.
  • Quarter crack are recognized more in the hindlimb.
  • Toe cracksare the result of poor conformation   Musculoskeletal: conformation  or chronic founder   Foot: laminitis  ; characterized by long feet due to lack of correct and regular farriery.
  • Toe cracks are more common in the forelimb.

Timecourse

  • Grass cracksusually begin as small distal cracks that propagate proximally though neglect, inadequate treatment or ignorance.
  • Sand cracksappear slowly after damage to the coronary band, or more quickly following hairline damage of the proximal hoof capsule.
  • Quarter cracksmay present with sudden onset-acute lameness, especially if unstable or infected.
  • Horizontal cracksgrow down the hoof wall slowly subsequent to coronary band damage or eruption of a submural abscess or seroma.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Kempson S A & Robb R (2004)Use of topical disinfectant as part of a hoof care programme for horses with diseases of the hoof capsule.Vet Rec154(21), 647-652PubMed.
  • Pollitt C C & Daradka M (2004)Hoof wall wound repair.Equine Vet J36 (3), 210-215PubMed.
  • Moyer W (2003)Hoof wall defects: chronic hoof wall separations and hoof wall cracks.Vet Clin North Am Equine Pract19(2), 463-477PubMed.
  • Pardoe C H & Wilson A M (1999)In vitromechanical properties of different equine hoof wall crack fixation techniques.Equine Vet J31(6), 506-509PubMed.
  • Pollitt C C (1998)The anatomy and physiology of the hoof wall.Equine Vet Educ10(6), 318-325VetMedResource.
  • Eustace R A (1994)Factors affecting equine hoof horn growth rate and quality.In Pract16(3), 129-131VetMedResource.


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